Field of the Invention
One or more aspects of the present invention relate to a wireless power antenna and a dual mode antenna including the same.
Background Art
Recently, much attention has been paid to energy-IT convergence technology. The energy-IT convergence technology means fusing of the existing energy technology with IT technology that has been rapidly advanced. Wireless power transfer (WPT) technology is a field of energy-IT convergence technology. The WPT technology is technology of supplying power in a wireless manner without using the existing power lines. Since a home appliance or the like may be wirelessly charged using the WPT technology without connecting the home appliance or a power cable as a charger to an electrical outlet, research has been actively conducted on the WPT technology.
Examples of WPT technology that have been commonly used or on which research has been conducted include a magnetic induction method and a magnetic resonance method. WPT technology employing the magnetic induction method is a method using magnetic induction occurring between two coils, and enables power of several watts to be transmitted within a range of a distance of several mm to several cm. Thus, the WPT technology employing the magnetic induction method has been applied to transportation cards, wireless razors, electric toothbrushes, etc. The WPT technology employing the magnetic resonance method is a method of transmitting power using a resonant coupling at a resonant frequency. When the WPT technology employing the magnetic resonance method is used, power of several tens of watts may be transmitted within a range of a distance of several meters or less. In this case, the efficiency of transmitting power is influenced by a quality factor of a resonator. In this connection, inductor structures having an improved quality factor have been disclosed in US 2008/0157272 (hereinafter referred to as ‘prior document 1’), KR 0637078 (hereinafter referred to as ‘prior document 2’), U.S. Pat. No. 4,392,013 (hereinafter referred to as ‘prior document 3’), etc. However, in prior documents 1 and 2, a metal layer is disposed only on one side of a substrate and thus a turn ratio required to form an antenna is not likely to be secured. Prior document 3 simply discloses a method of manufacturing a fine-pattern film.
In a large number of mobile terminals that have been recently put on the market, a near-field communication (NFC) module is installed to establish NFC.
NFC is a proximity communication technology whereby data can be transmitted or received within a range of a distance of about 10 cm using a frequency of 13.56 MHz. The NFC module may be installed in mobile terminals and used in various fields of user authentication, identification, credit cards, mobile tickets, mobile coupons, etc.
An NFC antenna (coil) is required to establish NFC. In the NFC antenna, an antenna for an NFC reader and an antenna for an NFC tag are independently included. Actually, an integrated dual antenna structure including a stack structure of an NFC reader antenna and an NFC tag antenna is generally used in mobile terminals.
Also, an additional wireless power transmission antenna (coil) is required to wirelessly transmit power. Thus, in order to support both an NFC function and a wireless power transmission function, antennas for the respective functions should be installed together in a mobile terminal. In this case, an antenna installation space is small since the size of the mobile terminal is limited, and the size and thickness of the mobile terminal increase due to two types of antennae.
Thus, there is a need to develop a technique of minimizing a necessary antenna installation space while installing an NFC antenna and a wireless power transmission antenna together.
Such a technique has been disclosed in US 2010-0194334 (hereinafter referred to as ‘prior document 4’). Prior document 4′ discloses a power circuit for wirelessly transmitting power and establishing NFC. An electronic device including the power circuit includes a back housing having a wireless power receiving antenna and a converting circuit. Although prior document 4 discloses that the wireless power receiving antenna may be used to perform a function of wirelessly supplying power or an NFC function, a structure of simultaneously performing these functions is not particularly disclosed.